B1 - Active Transport

What is active transport?

The movement of substances from a more dilute solution to a more concentrated solution, against the concentration gradient.

Does active transport require energy?

Yes, active transport requires energy from respiration.

How is active transport different from diffusion?

Active transport moves substances against the concentration gradient and requires energy, while diffusion moves down the gradient and does not need energy.

What does "against the concentration gradient" mean?

Moving from a low concentration to a high concentration.

Where does the energy for active transport come from?

From respiration, mainly in the mitochondria.

Why do cells that carry out a lot of active transport have many mitochondria?

To release energy through respiration needed for active transport.

Give one example of active transport in humans.

Absorption of sugars (e.g. glucose) from the small intestine into the blood.

Where does active transport happen in the human digestive system?

In the small intestine, from the lumen into the cells lining the gut.

Why is active transport needed in the small intestine?

Because the concentration of sugars in the lumen can be lower than in the cells, so diffusion would not work.

What happens after sugars are absorbed into intestinal cells by active transport?

They are transported into the blood to be carried around the body.

What is the lumen?

The cavity or space inside the small intestine where digestion takes place.

What is another example of active transport in plants?

Root hair cells absorbing mineral ions from the soil.

Which mineral ion is commonly taken up by active transport in plants?

Magnesium ions, which are needed to make chlorophyll.

Why is active transport needed in root hair cells?

Because the concentration of ions in the soil is lower than in the cell, so they cannot diffuse in.

How are mineral ions transported into the plant once inside the root hair cell?

They are moved to the xylem and transported to the leaves.

Why do root hair cells have many mitochondria?

To provide the energy needed for active transport of ions.

What is the role of magnesium in plants?

Magnesium is needed to make chlorophyll, which is essential for photosynthesis.

How does active transport help plants survive?

It allows them to absorb essential minerals even when they are in low concentrations in the soil.

What is the role of mitochondria in cells that use active transport?

To release energy through respiration for active transport to occur.

What is the key difference between active transport and osmosis/diffusion?

Active transport requires energy and moves substances against the concentration gradient.

What type of membrane is involved in active transport?

A partially permeable membrane (like the cell membrane).

Is active transport a passive process?

No, it is an active process because it uses energy.

Why might active transport be vital for survival?

It allows organisms to absorb nutrients or ions even when they are in low supply in the environment.

In what condition would glucose be absorbed by active transport rather than diffusion?

When the concentration of glucose is lower in the gut than in the blood.

What happens if energy is not available for active transport?

Substances cannot be moved against the concentration gradient, and essential nutrients may not be absorbed.

What would happen to a plant if active transport stopped working?

It would not absorb enough mineral ions, leading to poor growth and yellow leaves due to lack of chlorophyll.